The Collaborative International Dictionary
Pseudomorph \Pseu"do*morph\, n. [See Pseudomorphous.]
An irregular or deceptive form.
(Crystallog.) A pseudomorphous crystal, such as a crystal consisting of quartz, but having the cubic form of fluor spar, the fluor crystal having been changed to quartz by a process of substitution.
Douglas Harper's Etymology Dictionary
"irregular form," 1838, earlier in German and French, from pseudo- + Greek morphe "form" (see Morpheus). Related: Pseudomorphic.\n
Wiktionary
n. (label en geology mineralogy) A mineral that formed by replacement of an existing mineral (or organic matter) such that the new mineral has the appearance and dimensions of the original.
Wikipedia
In mineralogy, a pseudomorph is a mineral or mineral compound that appears in an atypical form ( crystal system), resulting from a substitution process in which the appearance and dimensions remain constant, but the original mineral is replaced by another. The name literally means "false form".
Terminology for pseudomorphs is "replacer after original", as in brookite after rutile.
Usage examples of "pseudomorph".
He blamed the sciences for re-establishing the mirage of truth, and still more the pseudomorph subjects like anthropology and economics whose adepts substituted inapplicable statistics for the ineptness of their insights.
They were indisputable crystalline formations, not biological pseudomorphs like glassine hairs.
The contexts in which these lithic pseudomorphs were found suggested great antiquity, which made the pioneering geologists question their validity as artifacts.
And he read them the let-pass, or letter of statements, as he had done to the pseudomorphs, and to the People of the Moon.
They were indisputable crystalline formations, not biological pseudomorphs like glassine hairs.